Antimonial lead alloys



Nov. 30, 1954 A. A. SMITH, JR., ET Al.

ANTIMONIAL LEAD ALLOYS Filed Feb. 15, 1950 |2.5% Sb, 0.75% Sn, 3.0%, AS. 0.0002% S. |2.5% Sb, 0.75% Snl 3.0% As. 0.00257L7 S. Magnificaiion |00 X Elchani', Ace'fic Magnficaiion |00 X Eichani', Aceiic Acid HzOz.

gmini/bow, Albert A. Smith, Jr.

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United States Patent O AN TIMONIAL LEAD ALLOYS Albert A. Smith, Jr., Metuchen, and Herbert E. Howe, Plainfield, N. J., assignors to American Smelting and Refining Company, New York, N. Y., a corporation of New Jersey Application February 15, 1950, Serial No. 144,246v 6 Claims. (Cl. 75-166) This invention relates to antimonial lead alloys and has, as a primary object, the provision of certain of such alloys with improved properties.

It has be'en found that by incorporating a critical amount of sulphur in certain antimonial lead compositions, that ductility is greatly enhanced and a marked renement in grain size results with accompanying increase in fatigue strength.

Composition limits of the essential constituents of the various antimonial lead alloys embraced by the invention are: (a) l2-25% Sb, 0.001-0.01% S, balance Pb; (b) alloy (a) with 0.1-20% Sn replacing an equivalent amount of lead; and (c) alloy (b) with 0.1-3.5% as replacing an equivalent amount of lead. Minor impurities and non-essential constituents may be present to the extent that they do not adversely affect or destroy the bcnecial eects of the sulphur content.

The marked grain rening elect achieved by the critical sulphur content of the alloys of the invention is best observed by referring to the drawings accompanying this specification in which the several gures show photomicrographs of three pairs of lead-base alloys, each pair of which differ only in sulphur content, with the alloy of the invention in each case being shown in the ligure bearing the sux a. The composition of each alloy is shown in each figure except for lead which constitutes the balance of the alloy in all cases.

The superiority of the alloys of the invention with regard to fatigue strength is well illustrated by the following example. Identical samples of an alloy (nominal composition 15% Sb, 1% Sn, 1% As, bal. Pb) were prepared except for the sulphur content which was 0.0002% and 0.0029%, respectively. Test samples of each were poured and the resulting castings tested on a standard R. R. Moore rotating beam fatigue machine with the following results:

The greatly increased ductility exhibited of the alloys Average Angle of Bend in S content of alloy (percent) Degrees Aglldof From a study of the comparative examples shown in the drawings and the results of the tests outlined above, the beneficial elects to be gained by incorporating a proper amount of sulphur in certain antimonial lead alloys are readily apparent. Investigations have shown that the amount of sulphur has to be at least 0.001% and the antimony content of the alloy not less than 12% to initiate the improvement in properties. The limits of the essential constituents in all of the alloy compositions embraced by the invention are as shown earlier in this speciiication and in the appended claims.

What is claimed is:

l. An alloy consisting essentially of 0.001-0.01% sulphur, more than 12% and up to 25% antimony, balance lead.

2. An alloy according to claim l in which an equivalent amount of lead is replaced by 0.1-20% tin.

3. An alloy consisting essentially of 0.001 to 0.01% sulphur, 0.1 to 20% tin, 0.1 to 3.5% arsenic, more than 12% and up to 25% antimony and the balance lead.

4. An alloy consisting essentially of 0.01% sulphur, more than 13% and up to 25% antimony, and the balance lead.

5. An alloy consisting essentially of 0.001% to 0.01% sulphur, more than 13% and up to 25 antimony, and the balance lead.

6. An alloy as defined in claim 5 which additionally contains small amounts of metal selected from the group consisting of arsenic, tin and mixtures thereof.

References Cited in the le of this patent UNTTED STATES PATENTS Number Name Date 1,722,358 Seljesaeter July 30, 1929 OTHER REFERENCES Fink et al., treatise in Trans. Amer. Electrochemical Society, 1941, vol. 79, pages 272, 273 (complete article, pages 269-305). 

1. AN ALLOY CONSISTING ESSENTIALLY OF 0.001-0.01% SULPHUR, MORE THAN 12% AND UP TO 25% ANTIMONY, BALANCE LEAD. 